The rapid expansion of the data communications industry, in particular the Internet and the World Wide Web (WWW), sometimes referred to as the superinformation highway, has provided data processing system users with what is effectively global communication link interconnecting a vast number of databases and other network users. The local link between the network and the user is typically by way of a phone line (e.g., analog or ISDN, for example) of a public communication service provider, with the workstation hardware including a modem or terminal adapter equipment that allows dial-up access between the user and a remote party. Since a user's workstation is coupled directly to such interface equipment, not only can the workstation user access any other party having similar network access, but any other party can call the user's workstation.
More particularly, as diagrammatically illustrated in FIG. 1, a user workstation 10 may typically be coupled via a communication link 11 to a local area network (LAN) 20 by way of a LAN interface 13, which also provides access to an external, public communication services (PCS) network, such as the Internet 30. LAN 20 customarily includes one or more computer-based units, such as the illustrated workstations 21 and 22, network server 23 and printer 24, which are interconnected via a hub 25. The hub 25 is connected to interface 13, so that the end user workstation 10 may access any unit of the local area network 20. Similarly, to connect to the external network 30, the network interface 13 may be coupled through an electronic mail gateway 32 and a modem 33, so that a dial-up connection may be provided to an Internet connection provider 34, through which direct access to the Internet 35 is achieved.
Because a public communication system is a potential window into any computer linked to it, it is customary to both wrap or embed all communications in a `security blanket` (some form of encryption) at the source end, and to employ one or more permission code (password) layers that must be used to gain access to another computer. Unfortunately, a fundamental characteristic of essentially all encryption operators or algorithms is the fact that, given enough resources, almost any encryption algorithm can be broken. This, coupled with the fact that each encryption algorithm has a `footprint`, which is discernible in the scrambled data by a sophisticated data communications analyst, means that no data communication can be guaranteed as secure.